Electric incandescent lamp



June 15, v1943- c. L. FA'NTUR ET AL ELECTRIC INCANDESCENT LAMP FiledNov. 5, 1942 lnvervbors Erwin E Lehmann, Chartes Lfan'kur, 10 W His Ahtorney.

Patented June 15, 1943 ELECTRIC INCANDESCENT LAMP Charles L. Fantur,Hanover, N. H., and Erwin E. Lehmann, East Cleveland, Ohio, assignors toGeneral Electric Company, a corporation of New York Application November5, 1942, Serial No. 464,566

4 Claims.

This invention relates to vitreous electrical devices, and is especiallyadaptable for relatively small devices such as electric lamps, includingincandescent lamps of candelabra and miniature types, and lamps for lowvoltages. An important aim of the invention is to provide a very ruggedlamp capable of standing extreme vibration and shock, as on vehicleswhich travel over rough terrain and may have little or no protectionagainst shock in the way of springs or the like. It afiords theadvantage that the lamps can be made with the same machinery andaccording to substantially the same methods as other lamps of similartypes. Various other features and advantages of the invention willappear from the description of species and forms of embodiment, and fromthe drawing.

In the drawing, Fig. l is a tilted or perspective view of anincandenscent lamp embodying the invention, the lamp being shown withoutthe usual base for the sake of clearness of illustration; Fig. 2 is atilted view of a lamp of somewhat difierent construction, equipped witha base; and Fig. 3 is a view similar to Fig. 1 illustrating anothermodification.

The incandescent lamp shown in Fig. 1 comprises a spherical bulb I witha neck II having a butt seal I2 which may be formed in any usual orpreferred way-for example, as disclosed in U. S. Patent 1,742,153 toStiles et al. The lamp has a plurality of associated filament mounts I5,two being here shown. Each mount I5 may be of the usual simpleconstruction used in small lamps of the type illustrated, consisting ofa pair of wire leads I6, Il fused through an insulative or vitreous beadI8, and a bowed coiled filament connected between the inner ends of theleads. From each mount I5, the current leads I6, I! extend out throughthe viterous wall at the junction of the bulb neck II and its closure orseal I2, being sufiiciently spaced from those of the other mount toinsure against their coming in contact near the seal. Short circuitbetween the two mounts I5, I5 further inward from the seal I2 iseffectively prevented by their beads I8, I8 which are each of a size toengage the other mount, so that they serve as buffers or spacers to keepa lead of either mount from touching a lead of the other. the two mountslie in substantially the same plane perpendicular to the leads IS, ITand to the axis of the bulb Ill and its neck I I, and may normallyengage or lie against one another with an elastic pressure due toresilience of the lead wires I6, II, I5, II. Thus there is no tendencyfor the mounts As here shown, the beads I8, I8 of I5, I5 (or their beadsI8, I8) to strike one another with an impact or shock that might shatterthe beads, or break the filaments 20, 20. Behind the mount beads I8, I8,and preferably outside the seal I2, the leads I1, I! of the two mountsI5, I5 are connected together at 2!, as by welding, so that the twofilaments 20, 20 are connected in series between the other leads IS, IS.This may be done after the lamp has been exhausted and sealed off at I2.

Fig. 2 illustrates a variant construction in which the bent or bowedfilaments 20a, 20a are longer than those shown in Fig; l, as for lampsof higher voltage, and-have their bights or bends supported,substantially at 'mid-length of each filament, by elastic, resilientsupport wire 22, 22 each having one end anchored and fixed by beingfused into the corresponding bead I8, and having its other end bent intoa pigtail loop 23 loosely embracing the filament. In Fig.

resembling an ordinary conventional interrogation point, with loopedeyes 23b, 23b at their free ends surrounding and engaging the bends ofthe filaments 20, 20. In other respects, the construction is essentiallylike what is shown in Figs. 1 and 2.

To dispense with repetitive description, various parts and features inFigs. 2 and 3 are marked with the same reference numerals as theircounterparts in Fig. 1, a distinctive letter being added where suchdistinction seems necessary.

In all the forms of-construction, the filaments 20, 20 are much strongeras against breakage by shock than one filament of the same wire size andtwice the length-or of the same length and half the cross-sectionalarea-which would take the same voltage as the two filaments in series.In

a 3 volt lamp, two filaments of 1 /2 volts each may be used; in a 12-16volt lamp, two 6-8 volt filaments may be employed; in a 24-28 volt lamp,two 12-16 volt filaments are suitable. The Fig. 2 construction with theintermediate supports 22, 22 is particularly suitable for 12-16 voltlamps, and that of Fig. 3 for 24-28 volt lamps, while lamps of lowervoltage do not usually need intermediate supports, because theirfilaments are much short- .er and stronger against shock, and may bemade as in Fig. 1.- All tests show that the series connection oi thefilaments of associated mounts makes a very much stronger constructionthan a single filament and mount.

What we claim as new and desire to secure by Letters Patent the UnitedStates is:

1. A device of the character described comprising a bulb with a seal,filament mounts in said bulb comprising pairs of leads sealed throughsaid seal and an insulative bead mechanically conmeeting the leads ofeach pair while electrically insulating them from each other, each ofsaid beads being of a size to engage another mount and prevent shortcircuiting contact between the mounts, and leads 01' said mounts beingconnected together behind their beads, so as to place the filaments'ofsaid mounts in series electrically between the other leads of saidmounts.

2. A device oi. the character described comprising a bulb with a buttseal, filament mounts in said bulb comprising pairs of leads sealedthrough said seal and an insulative bead mechanically connecting theleads of each pair while electrically insulating them from each other,said beads lying substantially in a common plane perpendicular to theleads, so as to prevent short circuiting contact between leads, andleads of said mounts being connected together outside said bulb, so asto place the filaments of said mounts in series electrically between theother leads of said mounts.

3. A device of the character described compriscuiting contact betweenleads, and leads of said mounts being connected together outside saidbulb, so as to place the filaments of said mounts in series electricallybetween the other leads of said mounts.

4. A device of the character described comprising a bulb with a seal,filament mounts in said bulb comprising pairs of leads sealed throughsaid seal and an insulative bead mechanically connecting the leads oreach pair while electrically insulating them from each other, each ofsaid beads being of a size to engage another mount and prevent shortcircuiting contact between the mounts, leads of said mounts beingconnected together behind their heads, so as to place the filaments oi!said mounts in series electrically between the other leads of saidmounts, and each mount comprising a resilient gallows support engagingthe bend of a filamentat its own free end, and having its other endanchored in the mount bead.

CHARLES L. FANTU R. ERWIN E. LEHMANN.

